The dead king in question is Louis XVI (the last of the French kings), who was ceremoniously beheaded on January 21st, 1793. After the beheading, attendees rushed the stage and dipped their handkerchiefs in the royal blood.

Over two hundred years later, some of that blood may have been found–dried to the inside of a decorative gunpowder gourd. The story goes that one of the attendees rushed home and stuffed the bloody handkerchief into the gourd for safekeeping.

In a study published in the journal Forensic Science International: Genetics, researchers analyzed some of the dried blood scraped from the inside of the gourd to find out if it really could be the king’s blood. They checked the Y chromosome to see if the blood-donor was male, and checked for the presence of a blue-eye gene, HERC2. The blood was indeed from the correct time period and belonged to a blue-eyed male–so far, the evidence fits the blue-eyed king. More genetic information about the family will be needed to confirm the identity, the study’s lead author told Wired’s Dave Mosher:

A group of researchers is questioning, again, if aliens visited India in 2001–in the form of red rain.

In 2001, a bizarre red rain showered India’s southern state of Kerala. Godfrey Louis, a physicist now in Cochin University of Science and Technology’s astrobiology department, decided to collect samples and take a closer electron-microscope look. He noticed some particles in the rainwater that looked like biological cells, but when he went looking for DNA, he found none. That enticingly strange result led Louis to speculate that he had found extraterrestrial bacteria.

The new paper (pdf) appears in Arxiv.org, not a peer-reviewed journal. But it repeats earlier work by Louis and a collaborator that they say shows the cell-like particles can survive and grow at high temperatures that would kill most life as we know it (around 250 degrees Fahrenheit). At room temperature, particles appear as inert as, well, odd looking red rain dirt.

The necessary parts: one salad spinner, some hair combs, a yogurt container, plastic lids, and a glue gun. The finished product: a manual, push-pump centrifuge that could be a lifesaver in developing world medical clinics. Its name: the Sally Centrifuge.

A team of college students invented this low-cost centrifuge, which can be built for about $30, as a project for a global health class at Rice University. The teacher challenged them to build an inexpensive, portable tool that could diagnose anemia without access to electricity, and the tinkerers got to work.

Men diagnosed with erectile dysfunction probably wouldn’t be too keen to hear that they might have bigger problems, but a new study in the journal Circulation reinforces that unfortunate idea. Given that both ED and heart attacks can result from restricted arteries that prevent blood from flowing freely, doctors have long suspected that they might be connected. Now, the study says, there’s evidence that one precedes the other. From The Los Angeles Times:

The results are probably not too surprising, added Dr. Robert Kloner, a cardiologist at USC’s Keck School of Medicine, “because arteries in the penis are smaller, so atherosclerosis shows up there sooner,” perhaps three to four years before the onset of cardiovascular disease.

The take-home message, both experts said, is that when a patient seeks treatment for ED, typically from a general practitioner, he should be given a full physical work-up to look for heart disease and referred to a cardiologist.

The guidelines for treating men with ED already state that they should be examined for cardiac problems. Kloner says updated guidelines in a few years could make that recommendation more forceful, so doctors can make sure a penis attack doesn’t become a heart attack.

The animal kingdom is full of weird stuff, like animals that turn into zombies—and one thing many of them will do is go to great (and gross) lengths to avoid predators.

Armored crickets, which are native to Namibia, South Africa, and Botswana, have a particularly disgusting means of driving away predators: They spew vomit and spurt hemolymph (the mollusk and arthropod version of blood) from under their legs and through slits in their exoskeleton. Katydids do it too; in fact, in Germany the species has acquired the nickname “blutspritzer,” or “blood squirter.”

But that’s not all. Wounded crickets can attract other crickets foraging for protein and salt—and the healthy crickets are happy to become cannibals. According to BBC:

“When swarms [of crickets] in the African bush meet a road, lots get squashed and the others gather for a feast, so more get squashed until there can be a thick, acrid pancake of dead and moribund crickets on the roadside, bleeding and attracting more cannibals,” says [entomologist Bill] Bateman.

The Regal Horned Lizard, too, uses the blood-spewing tactic, shooting the substance from a pocket near its eyes…straight at its attacker’s eyes and mouth.

Check out this video of the lizard shooting blood. (Caution: It’s graphic, as videos of animals spurting blood are wont to be).

Murderers desperate to get rid of evidence might want to consider using bleach to wash away stains. But not just any bleach will do. When old-school chlorine-based bleach is splashed all over blood-stained clothing, even if the clothes are washed ten times, DNA is still detected.

So for the criminal aspiring for perfection, here’s the secret you’ll need to know: It’s the oxygen-producing detergents that will get rid of any incriminating evidence for good.

Researchers at the University of Valencia tested oxygen bleach on blood-stained clothing for two hours and found that it destroys all DNA evidence. Forensic tests such as luminal tests rely on the ability of blood to uptake oxygen: A protein in the blood called hemoglobin (responsible for transporting oxygen throughout the body) reacts with hydrogen peroxide and gives a positive test result.

Vampirism isn’t just for bats and Edward Cullen anymore.Some ordinary insects are also beginning to covet human blood, sweat, and tears, because these fluids contain valuable salt that is hard to find in their natural environment.Surprisingly, many species are even preferring salt to energy-rich sugar.

The idea that salt attracted bugs first dawned on a team of sweaty scientists studying insects in Peruvian forests.Puzzled by the swarms of tiny bees attacking them, the scientists soon realized that the bees were trying to get a taste of their sweat.Animals need salt to activate nerves and muscles, and to maintain water balance in their cells.

Intrigued, the scientists littered the forest floor with hundreds of vials filled with either sugar or salt and counted the ant species they baited.They found that ant species living within 100 kilometers of the oceans (with easy access to salt) chose sugar over salt.But ant species living farther inland had a noticeable preference for salt.Reporting in the Proceedings of the National Academy of Sciences, the scientists say the salt cravings were only seen in vegetarian ants, since carnivorous ants can get enough salt from the bodies of their prey.

Centrifuges are a pain to carry around. They also cost hundreds of dollars and need to be plugged in. All of which means that medical facilities in poor rural areas often go without this essential piece of diagnostic equipment that’s used to separate blood plasma for detecting infectious diseases.

Now, Harvard scientists have developed a portable, manually-operated centrifuge that does the job, and it only costs $2.50.To top it all off, it’s even dishwasher safe.

The scientists purchased an ordinary eggbeater from a local grocery store, removed one of the rotor blades, and taped a thin plastic tube containing blood to the remaining blade. Spinning the handle of the eggbeater at a comfortably brisk pace can fling the tube of blood round and round at a rotational speed of 1200RPM.That’s enough to separate blood cells from blood plasma, the clear liquid part of blood used to run cholesterol assays or to screen for diseases such as Hepatitis B and cysticercosis. Right now, infectious diseases cause up to half of all deaths in developing countries.